1. Field of the Invention
The present invention relates to the field of electromagnetic flow meters, in particular, to the field of insert to define a fluid flow path within an electromagnetic flow meter.
2. Description of the Related Technology
Electromagnetic flow meters may be used to determine the rate of flow of fluid in a conduit. The conduit itself may be used to define the fluid path within the flow meter or an insert, placed within the conduit, may define the fluid path within the flow measurement zone.
Prior art flow meters, or flow meter inserts, generally have a substantially circular cross-section, which may be designed to match the cross-section of the fluid conduit. Circular cross-section inserts may be manufactured easily and may provide an effective way to contain the fluid, which may be under pressure. The walls of the circular fluid conduit may further be used to support the flow meter insert and, since it is not required to be self-supporting, the flow meter insert may be manufactured economically as a lightweight insert.
A disadvantage of such flow meters or flow meter inserts, however, is that, due to their generally circular cross-sections, approximations must be made in determining the flow rate of the fluid, they require typically 5–10 diameters of upstream pipe work to ensure an accurate measurement or they are susceptible to the pipe work conditions in surrounding the installation.
Flow meters or flow meter inserts with substantially square or rectangular cross-sections have been designed for specialist purposes for which a measurement with immunity to flow conditions is required. Such flow meters may provide improved performance when compared to the standard circular cross-section flow meters, but they tend to be bulky to provide the strength required to form a flow conduit and hence are not suitable as general-purpose flow meters.